Defensively, The Gunners have been hugely impressively so far this term, keeping clean sheets in their opening three league games.
And Belgian ace Vermaelen says Bould, who was appointed in place of Pat Rice who retired in the summer, has played a major role in helping them tighten up at the back.
"He is our assistant now and has a lot of experience at a high level with Arsenal," Vermaelen told Sky Sports NewsHD.
"We work a lot on our defensive play and you can see that with our three clean sheets."
Vermaelen was speaking from Belgium's training camp as they prepare for World Cup qualifiers with Wales and Croatia.
He was seen with strapping on his ankle, but he insisted that there was no issue and he would be fit to play.
"It is fine, it just my ankle form last week - but it is okay," he added.